http://lnk.nu/google.co.uk/28fr

 

Are results that come from a spectrometer such as the image above continuous? I ask because I need to find the area under a spectrum. If the data points are continuous then I would use integration, if it's discrete then I would use a summation.

 

I've confused myself as even though a continuum of wavelengths in an interval are applied to a molecule, surely it is impossible to record the absorption at every value in a that interval.

Because the data are discrete, as you note, if that's what you have it sort of forces you into using summation/numerical integration. If you had a function to express the spectrum then you could (possibly) do an analytical integration.